More than 10 million people are in the crosshairs of Hurricane Florence as storm force winds move within hours of battering the US east coast.

Despite the potentially devastating hurricane being downgraded to category two on the five-step Saffir-Simpson scale, the governor of Georgia has joined his counterparts in Virginia and the Carolinas in declaring a state of emergency.

About 1.7 million people have already been told to leave their homes in the latter three states, but some who thought they were safely out of the path of the storm are now desperately working to board up their homes and businesses before its arrival.

One grocery store in Myrtle Beach, South Carolina, sported a plea for divine intervention - with forecasters warning that the threat of devastation remains high despite the downgrade.

Nighttime winds have gone from 140mph (225kph) to 115mph (185kph), and further weakening is expected as Florence approaches the coast.

Jeff Byard, an administrator at the Federal Emergency Management Agency, said: "Do you want to get hit with a train or do you want to get hit with a cement truck?"

Tropical storm force winds are thought to be just hours away from making landfall in North Carolina.

Its governor, Roy Cooper, told residents "the time to prepare was almost over".

Speaking at a news conference on Wednesday, he said: "Disaster is at the doorstep and it's coming in."

According to the National Hurricane Center, the eye of the hurricane will likely not blow ashore until Friday afternoon local time, after which it will then push westward and bring with it the potential for catastrophic inland flooding.

There have been warnings that any flooding of hog manure pits, coal ash dumps and other industrial sites could have a lasting effect on communities, with tainted water possibly washing into homes and drinking supplies.

Image:People queue to buy propane in Myrtle Beach, South Carolina, ahead of the arrival of Hurricane Florence

Two other tropical storms - Isaac and Olivia - have also been in the vicinity this week, with the National Weather Service estimating that some 10.15 million people lived in areas under either hurricane or tropical storm warnings.

In addition to tens of thousands of homes and businesses, five military bases and half a dozen nuclear power plants are also in the path of the storm.

Image:Hurricane Florence is closing in, with large clouds gathering over North Carolina

Image:Donald Trump says the government is ready to assist when required

Duke Energy, the second-largest energy company in the US, said Florence could knock out electricity to three-quarters of its four million customers in the Carolinas.

Workers are being brought in from the Midwest and Florida to help deal with what could be weeks of power outages in the aftermath, the company said.

He said: "We are ready but this is going to be one of the biggest ones to ever hit our country.

"Residents in the path of these devastating storms should comply with all evacuation orders and other emergency instructions. Protection of life is the absolute highest priority and that's what we are doing."